BILLINGS, Mont. - A Montana man has pleaded guilty to federal robbery and gun charges for his role in the robbery of a Columbus convenience store as part of a multistate crime spree.

Jacob Kraus, 21, of Butte, pleaded guilty Wednesday to one count of interfering with interstate commerce by robbery and to carrying or using a gun in a violent crime. U.S. District Judge Richard Cebull scheduled his sentencing for May 20. Kraus remains in custody.

Kraus, along with co-defendants Jordan Adams of Butte and his cousin, Camille Adams of Anaconda, and two others were captured in Chadron, Neb., on Oct. 11, 2007, two days after a string of robberies in Montana, Wyoming and South Dakota.

The crime spree began after Jordan Adams walked away from a Helena prerelease center. Camille Adams was on probation.

Kraus said he and the Adams cousins were talking about stealing beer from a store in Butte. He said he didn't know about the gun until it was used in the Thriftway robbery, where about $40 in cash and other items were taken.

During the Columbus robbery, Kraus said he was drunk and "kind of out of it. I knew we were involved in a robbery. When I heard the gunshot, it kind of brought me back to reality." Kraus said he grabbed some beer and ran out. The robbery netted $500 and other items, according to court records.

The crime spree continued with the armed robbery of a convenience store in Sheridan, Wyo., and of the State Line Casino on the border between Nebraska and South Dakota.

The men were arrested after a 14-hour manhunt in Chadron, Neb.